NEC ND-71762(E) system manual General Information for Ccis

GENERAL INFORMATION FOR CCIS

Table 2-5 shows the algorithm for changeover of input clocks from the DTI. The Table shows how the PLO selects a specific route for input clocks according to the input clock status of four routes, thus establishing clock synchro- nization. For example, in a case where Route 1, which has been selected due to a fault occurrence to clock input Route 0, has also become faulty, Table 2-5 should be looked up as follows:

STEP 1: Look at Route 1 block under “Selected Route Before changeover” (the current input clock route) column.

STEP 2: Under “Each Route Input Clock Status” column, look for the block which shows that only Routes 0 and 1 are faulty.

STEP 3: Under “Route To Be Selected After Changeover” column located at the right extremity of the Table, Route 2 is indicated in the block corresponding to the block found in Step 2.

If a route of which priority order is higher than the current route has been restored to normal, the route is changed over to that specific route.

ND-71762 (E)CHAPTER 2

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Issue 2